Beta-hydroxy-beta-methylbutyrate (HMB) is a naturally occurring amino acid metabolite that is often formulated into a variety of nutritional products and supplements. HMB is commonly used in such products to help build or maintain muscle mass and strength in selected individuals.
HMB is a metabolite of the essential amino acid leucine and has been shown to modulate protein turnover and inhibit proteolysis. In most individuals, muscle converts approximately 5% of available leucine to HMB, thus producing about 0.2 to 0.4 grams of HMB per day in a 70 kg male. In studies where various kinds of stress were induced in animals, HMB supplementation increased lean mass. Clinical studies also suggest that HMB has at least two functions in recovery from illness or injury including protection of lean mass from stress-related damage and enhancement of protein synthesis. It has been suggested that HMB may also be useful in enhancing immune function, reducing the incidence or severity of allergy or asthma, reducing total serum cholesterol and low density lipoprotein cholesterol, increasing the aerobic capacity of muscle, and other uses.
Since HMB is most often used in individuals to support the development and maintenance of muscle mass and strength, many HMB products have been formulated with additional nutrients that may also be helpful in promoting healthy muscle. Some of these HMB products contain additional nutrients such as fat, carbohydrate, protein, vitamins, minerals and so forth. Calcium HMB is a commonly used form of HMB when formulated into oral nutritional products, which products include tablets, capsules, reconstitutable powders, and nutritional liquids and emulsions. Nutritional emulsions are particularly useful in this regard because such emulsions may contain a balance of fat, protein, carbohydrates, vitamins, and minerals, all of which are useful for helping maintain healthy muscle.
It has now been found, however, that nutritional emulsions containing calcium HMB are often not physically stable over time, that such emulsions are not readily stable with many protein systems, and that protein-containing and other sediment forms in the emulsions during or after formulation, especially when packaged and stored for extended periods of time.
It has also been discovered that these nutritional emulsions containing calcium HMB often develop an undesirably bitter off flavor or after taste after the emulsion has been packaged and stored for extended periods of at least 1-3 months.
There is therefore a need for nutritional emulsions comprising calcium HMB that remain physically stable during shelf life and do not develop a bitter flavor or after taste over time.